The emissions system at the heart of the global Volkswagen diesel mess comprises many complex components, all of which have to work perfectly and consistently all the time, or the vehicle will fail to meet pollution standards.

Here are the components VW used on its 2009-15 diesel-powered vehicles and the functions they are designed to perform:

Have an opinion about this story? Click here to submit a Letter to the Editor, and we may publish it in print.

Please enter a valid email address.

Please enter your email address.

Please select at least one newsletter to subscribe.

See more newsletter options at autonews.com/newsletters. You can unsubscribe at any time through links in these emails. For more information, see our Privacy Policy.

Sign up and get the best of Automotive News delivered straight to your email inbox, free of charge. Choose your news – we will deliver.

Get 24/7 access to in-depth, authoritative coverage of the auto industry from a global team of reporters and editors covering the news that’s vital to your business.

The Automotive News mission is to be the primary source of industry news, data and understanding for the industry's decision-makers interested in North America.

1155 Gratiot Avenue Detroit, Michigan 48207-2997

Automotive News ISSN 0005-1551 (print) ISSN 1557-7686 (online)

Fixed Ops Journal ISSN 2576-1064 (print) ISSN 2576-1072 (online)